clk: mediatek: mark mtk_infrasys_init_early __init

clk: mediatek: mark mtk_infrasys_init_early __init

On gcc-4.6, we get a harmless link-time warning:

WARNING: vmlinux.o(.text.unlikely+0x196a0): Section mismatch in reference from the function mtk_infrasys_init_early() to the function .init.text:mtk_clk_register_cpumuxes()
The function mtk_infrasys_init_early() references
the function __init mtk_clk_register_cpumuxes().
This is often because mtk_infrasys_init_early lacks a __init
annotation or the annotation of mtk_clk_register_cpumuxes is wrong.

Newer compilers inline this function so they don't warn, but
marking it __init is the right solution for all versions.

Fixes: e9862118272a ("clk: mediatek: Add MT2701 clock support")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>